1. Field of the Invention:
The present invention relates generally to electrophotographic printing and copying, and, more particularly, to an improved hot roll, or fuser roll, used to fuse toner onto paper or other print medium to produce a printed or copied image.
2. Description of the Related Art:
Electrophotographic printing or copying apparatus employs a hot roll, or fuser roll, in the paper path in order to fuse the toner onto the paper or other print medium so as to produce a suitable image. The fuser roll comprises a hollow tube, typically made of aluminum or other heat conductive material, which is heated from within by a heating means, such as a quartz lamp. The fuser roll is provided with a coating for assisting in fusing the toner to the paper.
The fuser roll is typically heated to about 190.degree. C. Fuser roll coatings that have been used to fuse toner to paper include silicone rubber and polytetrafluoroethylene (PTFE), commonly known as Teflon. Silicone rubber does not permit a good throughput, wears relatively fast, and requires frequent changing of the fuser roll. PTFE provides a hard, non-compliant surface. As a consequence, fusing is not as good as silicone rubber fuser rolls, and the resulting image is glossy. A glossy image is objectionable because of the specular reflection it produces, rendering bar codes, for example, difficult to read by certain laser scanners.
Thus, there remains a need for a coating for a fuser roll that provides good print quality that is non-glossy, improved fusing of toner to paper, and longer wear.